Abstract
BACKGROUND: Anti-human T lymphocyte porcine immunoglobulin (p-ATG) is a potent immunosuppressive agent derived from porcine sources used in various immunotherapy applications. It is compared with similar products derived from other species, such as rabbit anti-thymocyte globulin (r-ATG) and ATG-Fresenius (ATG-F), which have distinct biological and therapeutic properties. This study aims to elucidate the mechanisms of action and comparative efficacy of p-ATG in relation to r-ATG and ATG-F through a comprehensive in vitro analysis. METHODS: A comparative analysis of p-ATG, r-ATG and ATG-F was performed, focusing on E rosette inhibitory potency, lymphocyte toxic potency, blocking activities of 24 CD molecules, and flow quantitative potency. Flow cytometric analysis was used to quantify these characteristics and assess the potency of the immunoglobulins. RESULTS: p-ATG exhibited lower E rosette inhibitory and lymphocyte toxic potencies compared to r-ATG but was significantly more potent than ATG-F at equivalent concentrations. At protein concentrations above 12.5 µg/mL, p-ATG showed slightly lower potency than r-ATG and much higher potency than ATG-F in flow cytometry assays. Both p-ATG and r-ATG exhibited similar killing effects on lymphocytes within the peripheral blood mononuclear cells (PBMCs), including CD3 + T cells, with a dose-dependent response. Notably, p-ATG displayed more pronounced blocking activities against CD8, CD99, and TCR α/β compared to r-ATG. CONCLUSION: p-ATG offers certain advantages over r-ATG and ATG-F, particularly in its ability to inhibit specific CD molecules and its overall potency in immunosuppressive assays, providing valuable insights for assisting clinical decision-making regarding the selection of ATG types based on patient-specific needs and treatment objectives.